1464. The Clinical Features of Pneumonia Caused by Legionella pneumophila vs. Streptococcus pneumoniae: A Retrospective Study
Session: Poster Abstract Session: Respiratory Infections: CAP
Friday, October 5, 2018
Room: S Poster Hall
  • Research Poster Template 6-28-18-6.pdf (160.2 kB)
  • Background: Legionnaires’ disease (LD) is a serious and often lethal pneumonia caused by Legionella bacteria. From 2001-2016, the incidence of Legionnaires' disease has tripled in the United States. The clinical manifestations of pneumonia caused by L. pneumophilia (LP) may be similar to those caused by Streptococcus pneumoniae (SP). As mortality from Legionella pneumonia is high (15-50%), an investigation of factors that differentiate these two types of pneumonia is required.

    Methods: Objectives; 1.) To determine the clinical features that differentiate community-acquired pneumonia (CAP) caused by LP SG 1 versus SP; and 2.) To assess outcomes associated with CAP caused by LP serogroup 1 versus SP. W conducted a retrospective chart review of adult patients admitted between 1/1/2013 and 10/31/2017 for confirmed LP or SP pneumonia. Data were collected on demographic and clinical characteristics, comorbidities, month of admission, laboratory values, vital signs, and outcomes. Data were analyzed using Student’s t-test, the chi-squared test and logistic regression with the forward likelihood ratio algorithm.

    Results: Of 106 patients, 48.1% had LP, 64.4% were male, 56.6% were black and the mean age was 59.1 ± 15.3 years. The incidence of LP peaked in the summer. Results of univariable analysis are shown in the table.





    Mean Temp. (˚F)

    102.3 ± 1.7

    99.0 ± 9.0






    Male Gender




    Median CWIC score

    0.0 (1-4)

    1.0 (0-13)


    Mean Na (mEq/L)

    130.2 ± 4.6

    132.1 ± 18.9


    From multivariable analysis, predictors of LP were male gender (OR=18.2, p<0.0001), diarrhea (OR=3.7, p=0.05), BMI (OR=1.2, p=0.05) and CWIC score (OR=0.57, p=0.004). Patients with SP were more likely to require intubation (p=0.04), an ICU stay (p=0.004) and to die (p=0.002).

    Conclusion: Our data suggest that high temperature and diarrhea may be used to help differentiate LP and SP pneumonia. The higher incidence among men requires further investigation. LP demonstrated a higher morbidity and mortality than SP.

    Sima Salahie, MD, Internal Medicine, St John Hospital and Medical Center, Grosse Pointe Woods, MI, Susan Szpunar, PhD, St John Hospital and Medical Center, Grosse Pointe Woods, MI and Louis Saravolatz, MD, Medicine, St John Hospital, Grosse Pointe Woods, MI


    S. Salahie, None

    S. Szpunar, None

    L. Saravolatz, None

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